Admin login

Effect of Exercise and Hyperoxia on Skeletal Muscle Meatbolism in COPD

Author

Year published

Metadata

Abstract

Chronic obstructive pulmonary disease (COPD) is associated with pulmonary limitations to exercise, inactivity, and potentially muscle dysfunction. PURPOSE: To compare the effect of COPD on skeletal muscle metabolism with matched controls during an exercise modality that minimally taxes the pulmonary system. METHODS: Six patients with COPD (FEV1/FVC = 37.1 ± 2.38) and six age, weight, and activity level matched healthy controls performed both sub-maximal and graded to maximum plantar flexion exercise. 31P magnetic resonance spectroscopy (MRS) was used in normoxia and hyperoxia (100% O2) to evaluate the hypotheses that ...View more >Chronic obstructive pulmonary disease (COPD) is associated with pulmonary limitations to exercise, inactivity, and potentially muscle dysfunction. PURPOSE: To compare the effect of COPD on skeletal muscle metabolism with matched controls during an exercise modality that minimally taxes the pulmonary system. METHODS: Six patients with COPD (FEV1/FVC = 37.1 ± 2.38) and six age, weight, and activity level matched healthy controls performed both sub-maximal and graded to maximum plantar flexion exercise. 31P magnetic resonance spectroscopy (MRS) was used in normoxia and hyperoxia (100% O2) to evaluate the hypotheses that phosphocreatine (PCr) recovery kinetics (τ) and %PCr depletions would be 1) different between these two subject groups, and 2) improved by an increase in O2 availability. RESULTS: There was no difference between COPD and controls in PCr τ (COPD = 43.67 ± 10.71, C = 31.53 ± 3.76) or %PCr depletion (COPD = 31.82 ± 6.14, C = 44.11 ± 4.47). Hyperoxia did not alter either variable in the COPD patients or controls. Although the COPD patients demonstrated an attenuated maximum work rate (WRmax), there was no difference in the metabolic response to this graded test when the data were normalized for relative WR (COPD = −0.67, C = −0.70 % PCr depletion/% WRmax). CONCLUSIONS: Although the limited WRmax: of the COPD patients should not be ignored, the measured indices of metabolism do not support a clear metabolic dysfunction in COPD. Additionally, the chronically reduced O2 availability in COPD does not appear to impact skeletal muscle metabolic function.View less >